ACID.
Another important agent in cheese-making is acid. This you are pretty
sure to have, at some stage of the process, and the chief question seems
to be as to _when_ you will have it. It is said that milk fresh from the
cow manifests the presence of lactic acid. The quantity is very slight,
however, and under favorable circumstances the development is slow.
Where milk is properly cooled immediately after being taken from the
cow, and the factoryman has good facilities for keeping it cool, it will
be found, when the time comes to begin the process of working up, what
is called "sweet." It will not taste as fresh and clean as when first
cooled after milking; but no acid will be perceptible to either taste or
smell--not even enough to make it what is termed "old."
Some think age makes the milk all the better for cheese-making, and we
believe it is generally understood that milk fresh from the cow does not
work quite satisfactorily. However, we place no great stress on this
opinion. Old milk will work quicker than new milk; the acid will develop
sooner to the point desired by the cheese-maker, and this saving of time
doubtless has something to do with the decision in favor of age in milk
for the purpose of cheese-making.
Our impression is, that milk cannot be too sweet when the rennet is
added, and that if sufficient time is taken to develop the acid in the
whey before dipping, the fresh milk will be found to turn out the
finest-flavored and best-keeping cheese. The acid is not wanted in the
_curd_, but in the _whey_. If the milk is sour, to begin with, or quite
advanced toward sourness, the lactic acid must pervade every particle of
the whole mass. Now, it strikes us that the correct idea is to expel the
whey from the curd, as far as possible, before the acid makes its
appearance, and let the acid develop in the whey afterward, so as to
furnish a sort of pickle. The acid will develop sharply at some stage in
the process; and, as we have before said, the question to be decided
seems to be as to what point it is best to have it develop at.
We say, with the light we at present have before us, we think the acid
should never be allowed to develop much before the curd is cooked and
the whey is properly expelled; then let the whey take on acid to quite a
perceptible degree before dipping the curd. We doubt if it makes much
difference whether the acidulation takes place while the curd is
floating in the whey, or after the whey is drawn off and while the curd
stands and drains. There is rather more convenience in handling to leave
the whey on and stir the curd sufficiently to keep it from packing; but
the "cheddar" cheese, which is generally considered the best of any, is
made by stacking the curd, after cooking, and allowing the whey that
clings to it to take on acid. But where the milk is all right, to begin
with, and the curd is properly managed and cooked, we doubt if it makes
any material difference which process is adopted for allowing the acid
to develop. With such a curd, there is little danger of its being
injured by the acid, as any one can demonstrate by allowing curd to
stand unpressed over night, as is often done with small remnants, when
the pieces will be found covered with an almost vinegar-sour acid. Grind
this curd and put it to press, and there will be no signs of sour
cheese.
The development of the acid is absolutely necessary to secure good
keeping qualities and a mild, clean flavor. Dip a curd before the whey
has become perceptibly acid, or is on the verge of "changing," and we
think that a rank, bitter flavor will be sure to follow. The absence of
sufficient lactic acid leaves the albumen in a condition likely to
decompose, while the butyric acid develops itself, as in rancid butter,
and the two combine to make a very unpalatable flavor to one nice about
the taste of his cheese. Some prefer strong cheese. To such, the nearer
the flavor approaches that of smoked herring and tobacco, the greater
the gustatory gratification.
The principal difficulty in working up sour milk is to get sufficient
action of the rennet and heat on the curd to properly condense it and
expel the whey. It is a mistake, therefore, to dip a curd soft because
it is sour. Run your heat up to 104° or even 106°, as soon as possible,
and keep it there until your curd is cooked. It is sour, and nothing but
cooking will save it, if anything will. The whey must and will come out.
If you do not expel it from the particles of curd in the vat, you will
not be able to press it out sufficiently to keep it from working and
leaking out while the cheese stands on the ranges.
If anything will prevent sour milk from making leaky cheese, it is
thorough cooking. This process you should hurry up as much as
possible--always having an eye to keeping the heat even, and preventing
waste of butter. The acid, acting on the butter globules, makes their
coatings tender. Therefore, handle the curd as carefully as possible,
cool well before putting to press, and press gently, increasing the
pressure gradually. But, if you have succeeded in getting your curd
properly cooked, you have done one of the best things possible to
retain the butter. If, when you put the curd to press, you find you have
more than the usual bulk of curd, filling the hoops fuller and refusing
to yield readily to the pressure of the screw--as is generally the case
with sour milk, as managed in most factories--you may know that you have
not done your work thoroughly, and therefore look out for leaky, sour,
poor cheese. On the other hand, if you have condensed the curd to the
usual bulk, so that it works well under the screw, you may hope for a
fair cheese, that may pass muster when the buyer comes along.
We often hear the remark, when anything is said about developing the
acid, "No sour cheese for me; I prefer to dip my curd sweet." People who
talk in this way either make bitter, bad-flavored cheese, or else get on
more acid than they are aware of, in consequence of having dull taste
and smell. They judge by the _appearance_ and _feel_ of the curd when it
is in condition to dip, and may succeed in hitting the right point. In
hot weather, it is hardly possible not to develop the acid sufficiently.
But if they really dip the curd sweet, we do not believe it possible
that their cheese can be up to the standard demanded by the best
markets, though they may succeed in getting a fair price for it. Not all
buyers are really good judges, and fewer still know what the matter is
with a cheese that is imperfectly made. They know, perhaps, that there
is something wrong about it; but what, they are unable to say. Further,
we believe the average price of American cheese lower than it should be,
in consequence of so little really prime cheese, and of the large amount
of second-rate; and that, as yet, our buyers are not sufficiently
discriminating in their purchases and prices, though they are yearly
growing more so. Both buyers and cheese-makers need more experience and
a better understanding of what is requisite in the manufacture of a
prime article.